Image level backups used for disaster recovery present new challenges as compared to legacy file system level backups. In particular, the size of disk images that needs to be backed up requires longer times to backup. Backups of large disk images also significantly increase backup file storage requirements.
As compared to file level backups, which are typically set to backup only required file system objects, image level backups save complete images of backed up disks. Thus, unlike file-level backups, conventional image level backups typically include unnecessary data blocks belonging to file system objects that are of no value to users, deleted file system objects, file system objects marked for deletion, unallocated space, and unused space. While currently available commercial backup solutions are able to efficiently remove white spaces (e.g., by using compression and deduplication), other unneeded data blocks mentioned above are still processed as part of image-level backups. This slows down backup performance and requires additional backup storage space. Thus, there is a need for methods of excluding unnecessary data from image level backups.